Merge mode-based inter-prediction method and apparatus

Abstract

A video encoding/decoding method is provided, which includes constructing a merge candidate list of a current block, deriving motion information of the current block from the merge candidate list, and performing inter-prediction of the current block using the motion information, where the merge candidate list includes at least one of a spatial merge candidate, a temporal merge candidate, or a combined merge candidate, and the combined merge candidate is derived by combining n merge candidates belonging to the merge candidate list. A video encoding/decoding apparatus is also provided.

What is claimed is: 
     
         1 . A method of decoding a video signal, the method comprising:
 constructing a merge candidate list of a current block;   deriving motion information of the current block from the merge candidate list, wherein the motion information comprises at least one of a prediction direction flag, a reference picture index, or a motion vector; and   performing inter-prediction of the current block using the motion information,   wherein the merge candidate list comprises at least one of a spatial merge candidate, a temporal merge candidate, or a combined merge candidate, and the combined merge candidate is derived by combining n merge candidates belonging to the merge candidate list, and   the combined merge candidate comprises a first merge candidate and a second merge candidate, and motion information of the combined merge candidate is derived by a weighted average of motion information of the first merge candidate and motion information of the second merge candidate.   
     
     
         2 . The method according to  claim 1 , wherein the n merge candidates are merge candidates corresponding to indices of 0 to (n−1) in the merge candidate list. 
     
     
         3 . The method according to  claim 1 , wherein an index of the combined merge candidate is larger than an index of the temporal merge candidate. 
     
     
         4 . The method according to  claim 1 ,
 wherein the motion information of the combined merge candidate is derived according to a prediction direction of the first merge candidate and a prediction direction of the second merge candidate.   
     
     
         5 . The method according to  claim 1 , wherein a weight of the weighted average is any one of [1:1], [1:2], [1:3], or [2:3]. 
     
     
         6 . The method according to  claim 1 , wherein the motion vector is derived in units of sub-blocks of the current block. 
     
     
         7 . The method according to  claim 6 , wherein a size of a sub-block is a fixed size. 
     
     
         8 . The method according to  claim 6 , wherein a size of a sub-block is 4×4. 
     
     
         9 . The method according to  claim 1 , wherein performing inter-prediction of the current block using the motion information comprises:
 selecting a reference picture from a reference picture list based on the reference picture index of the current block;   determining a reference block within the reference picture based on the motion vector of the current block;   generating a prediction pixel of the current block using a pixel of the determined reference block; and   reconstructing the current block by adding the prediction pixel of the current block and a residual pixel.   
     
     
         10 . The method according to  claim 9 , further comprising:
 deriving the residual pixel by performing at least one of inverse quantization or inverse transformation on a residual coefficient signaled through a bitstream.   
     
     
         11 . An apparatus of decoding a video signal, the apparatus comprising:
 a memory configured to store a program for performing inter-prediction; and   a processor configured to perform, when running the program, a method of decoding a video signal, the method comprising:
 constructing a merge candidate list of a current block; 
 deriving motion information of the current block from the merge candidate list, wherein the motion information comprises at least one of a prediction direction flag, a reference picture index, or a motion vector; and 
 performing inter-prediction of the current block using the motion information, 
 wherein the merge candidate list comprises at least one of a spatial merge candidate, a temporal merge candidate, or a combined merge candidate, and the combined merge candidate is derived by combining n merge candidates belonging to the merge candidate list, and 
 the combined merge candidate comprises a first merge candidate and a second merge candidate, and motion information of the combined merge candidate is derived by a weighted average of motion information of the first merge candidate and motion information of the second merge candidate. 
   
     
     
         12 . The apparatus according to  claim 11 , wherein the n merge candidates are merge candidates corresponding to indices of 0 to (n−1) in the merge candidate list. 
     
     
         13 . The apparatus according to  claim 11 , wherein an index of the combined merge candidate is larger than an index of the temporal merge candidate. 
     
     
         14 . The apparatus according to  claim 11 ,
 wherein the motion information of the combined merge candidate is derived according to a prediction direction of the first merge candidate and a prediction direction of the second merge candidate.   
     
     
         15 . The apparatus according to  claim 11 , wherein a weight of the weighted average is any one of [1:1], [1:2], [1:3], or [2:3]. 
     
     
         16 . The apparatus according to  claim 11 , wherein the motion vector is derived in units of sub-blocks of the current block. 
     
     
         17 . The apparatus according to  claim 16 , wherein a size of a sub-block is a fixed size. 
     
     
         18 . The apparatus according to  claim 16 , wherein a size of a sub-block is 4×4. 
     
     
         19 . A method of encoding a video signal, the method comprising:
 constructing a merge candidate list of a current block;   deriving motion information of the current block from the merge candidate list, wherein the motion information comprises at least one of a prediction direction flag, a reference picture index, or a motion vector; and   performing inter-prediction of the current block using the motion information,   wherein the merge candidate list comprises at least one of a spatial merge candidate, a temporal merge candidate, or a combined merge candidate, and the combined merge candidate is derived by combining n merge candidates belonging to the merge candidate list, and   the combined merge candidate comprises a first merge candidate and a second merge candidate, and motion information of the combined merge candidate is derived by a weighted average of motion information of the first merge candidate and motion information of the second merge candidate.   
     
     
         20 . An apparatus of encoding a video signal, the apparatus comprising:
 a memory configured to store a program for performing inter-prediction; and   a processor configured to perform, when running the program, the method according to  claim 19 .